This invention relates to an intake system for multiple intake valve type engines, and more particularly to an induction system for an engine that improves performance throughout the entire speed and load range.
The techniques of tuning an induction system for an engine are generally well known. It is also well known that induction system tuning may optimize running at a certain speed and load range; however, performance outside of this speed running condition may be deteriorated. For example, if the length of the runners of the induction system are tuned to achieve maximum power output, performance at low and mid-range may suffer.
It is, therefore, a principal object of this invention to provide an induction system for an internal combustion engine that offers good performance over a wide speed and load range.
It is known that the maximum power output of an engine may be increased by providing pairs of intake valves for each chamber of the engine, each of which is served by a separate intake passage. Although such arrangements improve maximum power output, this may be accompanied by a sacrifice in low and medium speed performance, particularly with a reduction of torque under these other running conditions. To offset these disadvantages, it has been proposed to incorporate a control valve in one of the induction passages that is operated so that the low speed requirements of the engine are supplied primarily through a single one of the induction passages.
It is a further object of this invention to provide an improved induction system of this type wherein the individual intake passages are tuned so as to improve performance throughout the engine speed and load range.
In engine embodying pairs of intake passages serving each chamber and a fuel injection system, it is important to insure that the amount of fuel delivered by the injection system is responsive to the total charge delivered to each chamber. This is particularly important where a control valve is employed as aforedescribed so that the charge at one speed range is delivered primarily through only one of the intake passages, and the charge at maximum output is delivered through both intake passages.
It is, therefore, a still further feature of this invention to provide an improved fuel feed control for an injection type engine having multiple intake passages.
In conjunction with the provision of a plurality of intake passages for each chamber of the engine and the independent tuning of these passages, it is important that this be achieved with as uncomplicated a construction as possible. It is, therefore, a still further object of this invention to provide an improved intake device for an engine embodying multiple intake passages.